In the past year the Mucosal Immunity Section has been engaged in a number of research studies involving both inflammatory bowel disease and common variable immunodeficiency. In a study of inflammatory bowel disease we are assessing safety, efficacy and immunologic effect of infusions of allogeneic bone marrow-derived mesenchymal stromal cells. This study is being performed in collaboration with the NIH Bone Marrow Stromal Cell Transplantation Center in the NIH Transfusion Medicine Department (under the direction of Dr. Pamela Robey) which is preparing the carefully prepared and standardized mesenchymal stem cells that are being infused. In this project both ulcerative colitis and Crohn's disease patients are being studied with respect to mRNA responses determined by microarray as well as with respect to induction of regulatory T cells. This project has been approved by the NIAID IRB and we have so far enrolled four patients in the program. Two of these patients exhibited durable and significant clinical improvement. Enrollment of patients in this study has been somewhat hindered by the fact that the patients selected for study are somewhat unusual patients that have had to have failed standard therapies, including administration of anti-inflammatory antibodies. In any case, enrollment has been temporarily suspended due to the fact that the mesenchymal stromal cells obtained from the NIH Blood Bank had been stored in a preservative (pentastarch) that was potentially contaminated with fungal organisms. Thus, new mesenchymal stromal cells stored under more rigorous conditions will have to be prepared for future use in these and other studies. The mesenchymal stromal cells that had been administered to patients under this protocol were culture-negative prior to use and the patients did not develop evidence of infection. Appropriate notification of patients as well as the IRB and FDA was instituted. In a second study of inflammatory bowel disease we are collaborating with Dr. Harry Malech and his colleagues (Dr. Suksee DeRavin) in on-going studies of Crohn's disease-like colitis occurring in patients with chronic granulomatous disease (CGD). These studies include the evaluation of cytokine production in the inflamed mucosa of CGD patients. In the studies conducted so far, Crohn's disease in CGD patients and conventional patients appear to be quite similar. In addition, even CGD patients without symptoms of overt Crohn's disease exhibit immunologic abnormalities suggest the presence of covert disease. This has led us to conclude that CGD is, in effect, a risk factor for the development of Crohn's disease that manifests itself in all CGD patients. In a third study of inflammatory bowel disease we have focused on the immunologic properties of lamina propria cells in patients with ulcerative colitis. Previous studies have shown that ulcerative colitis (UC) is associated with the presence of lamina propria non-invariant (Type II) NKT cells producing IL-13 and mediating epithelial cell cytotoxicity. Using cells derived from biopsies of UC patients under evaluation at NIH and elsewhere, we sought to define the antigen(s) stimulating such cells and to quantitatively assess these cells in the lamina propria. Our studies showed that UC lamina propria is replete with Type II NKT cells responsive to lyso-sulfatide glycolipid and bearing IL-13Ra2. Since lyso-sulfatide is a self-antigen these data suggest that an autoimmune response is involved in UC pathogenesis. Dr. Michael Yao, now a gastroenterologist at the Washington VA Medical Center, will collaborate with us in studies of UC patients with a range of severity to determine the relation of the level of intestinal infiltration of NKT cells responsive to lyso-sulfatide and disease course and severity. In the area of CVID we have continued to focus on gastrointestinal manifestations of the disease. In prior studies of CVID we established that the CVID GI syndrome is driven by ccells producing IFN-gamma. In addition, we collaborated with Drs. Andriy Morgan and Natalia Stulzhenko in the Laboratory of Cellular and Molecular Immunology in studies of CVID that included microarray analyses of biopsy tissue of CVID patients with enteropathy showing that CVID enteropathy is characterized by up-regulation of genes related to type 1 interferons. Based on this prior work, we have applied for and have obtained a U01 NIH cooperative research grant (PAR-13-029) with Drs. Morgan and Shulzhenko (now at Oregon State University) to expand on these findings. This Grant is entitled Anti-IL-12p40 Treatment of CVID Enteropathy: Gene Expression and Microbiota Analysis, and is centered around a clinical study of the safety and efficacy of a FDA-approved monoclonal anti-IL-12p40 in the treatment of CVID enteropathy. In addition, this Grant includes a study of the effect of this biologic agent on gene expression of inflammatory cytokines and on the microbiota in patients. In initial execution of these studies, we have obtained small intestinal biopsy material from several CVID patients without enteropathy (control CVID patients) and have sent these materials to Oregon State University where it has been successfully analyzed both from point of view of microbiome diversity and from gene expression. In addition, we have located several patients with CVID and GI enteropathy that will shortly be admitted to NIH for study. In on-going studies utilizing our CVID patient resource we have contributed DNA samples to various collaborators for analysis of possible gene defects. So far, one of our patients has been shown to have a BACH-1 mutation and another a STAT5 mutation. We are currently participating in the study of these patients.